The push API endpoint to which slack messages should be added.
Can be set in: collection.cfg
By default, messages will be submitted to the push endpoint running
on the default local admin port (i.e.
If the configured admin port differs, or if you wish to configure slack to use the push endpoint on a different machine, it can be configured here.
Note that if targeting a different machine, the server secrets must match to allow service users to communicate between the machines in question.